307 Comms 2000 unit

[paddypaws77]

Hi!
My fog light switch has gone dodgy on my Comms 2000 unit on my 2006 307 SW 2.0HDi. I bought a second hand one that looks exactly the same, has all the same plugs etc. I have just fitted it to the car and it doesn't work. Are they actually coded to the car?? It even throws up electronic ignition faulty. None of the switches work either. Do I need to programme it to the car or have I just got the wrong unit???
Cheers
Phil

[GiveMeABreak]

You must have the correct part - there are literally hundreds of these, so you can't go by looks alone as they mostly all appear the same but have different electrical architecture and software depending on the intended application and vehicle.

[paddypaws77]

So, do I have to match the EXACT part number to get the correct one?
I can use the one I have to take apart and see if there will be a repair for the contacts that are giving me the dodgy fog light.
Thanks.
Phil

[GiveMeABreak]

Yes, you need to match the part numbers up with your original unit.

[ozvtr]

Hi!
My fog light switch has gone dodgy on my Comms 2000 unit on my 2006 307 SW 2.0HDi. I bought a second hand one that looks exactly the same, has all the same plugs etc. I have just fitted it to the car and it doesn't work. Are they actually coded to the car?? It even throws up electronic ignition faulty. None of the switches work either. Do I need to programme it to the car or have I just got the wrong unit???
Cheers
Phil

NO, the COMs doesn't need to be coded in.

There are basically two types of COMs units. VAN BUS and CAN BUS. VAN BUS are pre-2005 and CAN BUS are post 2005. They are not interchangeable! From the outside they look much the same, HOWEVER the plugs for the HORN are different. VAN BUS have two separate spade connectors for the horn, CAN BUS have one grey connector. Also the later VAN BUS COMs units may have "ribbon" cables to the horn and airbag. VAN BUS units have separate wires to everything on the steering wheel.
The "guts" of the two units are totally different!
If your EBAY unit has the correct horn connector then I would guess that the unit is faulty. If you have purchased a CAN BUS unit (your car is 2006 and should be CAN BUS) it might not have all the switches, but it should do something! It's possible that the remote central locking and engine might not work but that's a different story. It should do something. Of course if it's VAN BUS, "well there's your problem"!

The failure mode for the switches in the CAN BUS COMs (yours) is typically worn contacts inside the indicator and wiper stalks. If you look on EBAY you will see replacement stalks for sale. The VAN BUS units do not use this arrangement and don't fail in this manner.

FYI, the engine immobilizer polls the key through the "High Frequency" module in the COMs unit. If the COMs unit isn't working (or the High Frequency module is broken) then your engine will not run.